JP2019173870A - Disc brake - Google Patents

Abstract

To provide a disc brake which can avoid that a return amount of a piston after a brake becomes excessive while suppressing a drag of a friction pad.SOLUTION: A disc brake comprises: a friction pad 13 opposing a disc 11; a piston 41 for pressing the friction pad 13 to the disc 11; a cylinder 46 having a bore part 51 for movably accommodating the piston 41; and a seal member 42 arranged in a seal groove 55 of the bore part 51, and contacting with the piston 41. A regulation part 101 for permitting the separation of the friction pad 13 and the piston 41 within a prescribed distance δ, and regulating the separation exceeding the prescribed discharge δ is arranged at the piston 41 and the friction pad 13, respectively.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a disc brake.

  There is one in which a groove portion is provided inside the open end of the piston, and a shim is provided with a locking claw that is elastically engaged with the groove portion (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 10-184744

  It is desired to suppress an excessive return amount of the piston after braking while suppressing dragging of the friction pad.

  An object of the present invention is to provide a disc brake capable of suppressing an excessive return amount of a piston after braking while suppressing dragging of a friction pad.

  In order to achieve the above object, the present invention has a configuration in which a pad and a piston are provided with a regulating portion that allows the pad and the piston to be separated within a predetermined distance and restricts the separation exceeding the predetermined distance. did.

  According to the present invention, it is possible to suppress an excessive return amount of the piston after braking while suppressing dragging of the friction pad.

Sectional drawing which shows the disc brake of 1st Embodiment. The partial expanded sectional view which shows the caliper body, piston, and seal member of the disc brake of 1st Embodiment. Sectional drawing which shows the piston of the disc brake of 1st Embodiment. The rear view which shows the friction pad of the disc brake of 1st Embodiment. The top view which shows the friction pad of the disc brake of 1st Embodiment. The perspective view which shows the friction pad of the disc brake of 1st Embodiment. Sectional drawing which shows schematically the principal part of the disc brake of 1st Embodiment. Sectional drawing which shows schematically the principal part of the disc brake of 1st Embodiment. Sectional drawing which shows schematically the principal part of the disc brake of 1st Embodiment. Sectional drawing which shows the piston of the disc brake of 2nd Embodiment. The top view which shows the friction pad of the disc brake of 2nd Embodiment. The perspective view which shows the friction pad of the disc brake of 2nd Embodiment. Sectional drawing which shows schematically the principal part of the disc brake of 2nd Embodiment. Sectional drawing which shows schematically the principal part of the disc brake of 2nd Embodiment. Sectional drawing which shows schematically the principal part of the disc brake of 2nd Embodiment.

[First embodiment]
A first embodiment will be described below with reference to FIGS. The disc brake 10 according to the first embodiment shown in FIG. 1 brakes the vehicle by stopping the rotation of a disc-like disc 11 that rotates with a wheel (not shown). Hereinafter, the direction of the central axis of the disk 11 is referred to as a disk axial direction, the radial direction of the disk 11 is referred to as a disk radial direction, and the circumferential direction of the disk 11, that is, the rotational direction is referred to as a disk circumferential direction. The center side of the disk 11 in the disk radial direction is referred to as the inner side in the disk radial direction, and the side opposite to the center of the disk 11 in the disk radial direction is referred to as the outer side in the disk radial direction.

  As shown in FIG. 1, the disc brake 10 includes a pair of friction pads 13 and 14, a caliper 15, and a mounting member (not shown). In the disc brake 10, a mounting member (not shown) is disposed across the outer peripheral side of the disc 11 and is mounted on a non-rotating portion of the vehicle. A pair of friction pads 13, shown in FIG. 14 and caliper 15 are supported so as to be slidable in the disk axial direction.

  Each of the pair of friction pads 13 and 14 is a pad main body 34 having a metal back plate 31 and a lining 33 that is a friction material attached to a surface 32 on one side of the back plate 31 in the thickness direction. It has.

  One friction pad 13 is disposed to face the disk 11, and the back plate 31 is supported by a mounting member (not shown) in a direction in which the lining 33 faces the disk 11. In this state, in the friction pad 13, the surface 35 opposite to the lining 33 of the back plate 31 faces the side opposite to the disk 11. Further, in this state, the friction pad 13 faces the disk 11 with the surface 36 on the side opposite to the back plate 31 of the lining 33. The friction pad 13 is supported by a mounting member (not shown) via a back plate 31 provided on the surface 37 opposite to the disk 11 of the lining 33. The friction pad 13 is an inner friction pad disposed on the inner side that is the inner side in the vehicle width direction of the vehicle than the disk 11.

  The other friction pad 14 is disposed to face the disk 11, and the back plate 31 is supported by a mounting member (not shown) in a direction in which the lining 33 faces the disk 11. The friction pad 14 is an outer friction pad disposed on the outer side, which is the outer side in the vehicle width direction of the vehicle than the disk 11.

  The friction pads 13 and 14 supported by a mounting member (not shown) are disposed on both sides in the axial direction of the disk 11 and can move in the disk axial direction. When the friction pads 13 and 14 move toward the disk 11 along the disk axial direction, the respective linings 33 come into contact with the disk 11.

  The caliper 15 includes a caliper body 40, a piston 41, and a seal member 42. In other words, the piston 41 constitutes a part of the caliper 15 of the disc brake 10.

  The caliper 15 is supported by a caliper body 40 so as to be slidable in a disk axial direction by a mounting member (not shown). The caliper body 40 includes a cylinder 46 disposed on the inner side in the disk axial direction with respect to the disk 11 and a bridge extending along the disk axial direction so as to straddle the outer periphery of the disk 11 from the outer side of the cylinder 46 in the disk radial direction. And a claw portion 48 that extends inward in the disk radial direction from the opposite side of the bridge portion 47 to the cylinder 46 and is disposed on the outer side in the disk axial direction with respect to the disk 11.

  The cylinder 46 is formed with a bore 51 that has a cylinder opening 50 that opens toward the claw 48 and is recessed on the opposite side of the disk 11 in the disk axial direction. In the bore portion 51, the piston 41 is disposed so as to be movable in the disk axial direction. The wall surface 52 of the bore part 51 has a guide inner peripheral surface 53 that is a cylindrical surface that guides the movement of the piston 41. The wall surface 52 of the bore portion 51 has an annular seal groove 55 that is recessed radially outward from the guide inner peripheral surface 53 on the cylinder opening 50 side.

  As shown in FIG. 2, the radially outer wall surface 57 on the cylinder opening 50 side (left side in FIG. 2) of the seal groove 55 is an annular flat surface that extends in the direction perpendicular to the axis of the guide inner peripheral surface 53. The radially inner side of the wall surface 57 is a tapered surface 58 located closer to the axial cylinder opening 50 toward the radially inner side.

  As shown in FIG. 1, the piston 41 includes a disk-like piston bottom 61 and a cylindrical piston body 62. The piston 41 is formed in a bottomed cylindrical shape in which an end of the piston body 62 opposite to the piston bottom 61 is opened. The piston 41 is movably accommodated in the bore 51 in such a direction that the piston bottom 61 is positioned on the opposite side of the cylinder opening 50 in the bore 51.

  As shown in FIG. 3, the piston 41 is formed with an inner flange portion 63 projecting radially inward from the piston barrel portion 62 at the end opposite to the piston bottom portion 61 of the piston barrel portion 62. Yes. The inner flange portion 63 is continuous over the entire circumference in the circumferential direction of the piston 41 and has an annular shape.

  The seal member 42 shown in FIG. 1 has an annular shape and is fitted in the seal groove 55 of the bore portion 51. A piston 41 is fitted on the inner peripheral side of the seal member 42. The seal member 42 comes into contact with the piston 41 over the entire circumference on the inner circumference side, and comes into contact with the groove bottom of the seal groove 55 over the whole circumference on the outer circumference side. As a result, the seal member 42 seals the gap between the cylinder 46 and the piston 41 and forms a hydraulic chamber 65 between the piston 41 and the cylinder 46. At the same time, the seal member 42 supports the piston 41 so as to be slidable in the disk axial direction with the guide inner peripheral surface 53 of the bore portion 51.

  The cylinder 46 is formed with a communication hole 66 that allows the fluid pressure chamber 65 to communicate with the outside, and brake fluid is introduced into the fluid pressure chamber 65 through the communication hole 66. The brake fluid introduced into the hydraulic chamber 65 advances the piston 41 toward the claw portion 48 side.

  One inner friction pad 13 is disposed between the piston 41 and the disk 11, and the other outer friction pad 14 is disposed between the claw portion 48 and the disk 11.

  The inner friction pad 13 includes a pad body 34 having a back plate 31 and a lining 33, and a shim 71 that also covers the surface 35 of the back plate 31 and also shown in FIGS. 4 to 6.

  As shown in FIG. 5 and FIG. 6, the back plate 31 has a flat plate shape, and a central plate portion 75 to which the lining 33 is attached, and both ends in the disc circumferential direction from both ends of the central plate portion 75 in the disc circumferential direction. It has a pair of ear | edge part 76 which protrudes outside. The back plate 31 is substantially mirror-symmetric with respect to the center in the width direction. The back plate 31 has a pair of ears 76 supported by a mounting member (not shown).

  The shim 71 is provided to suppress the heat of the pad main body 34 from being transmitted to the piston 41 and to suppress the brake noise of the friction pad 13. As shown in FIG. 5, in the shim 71, the flat main plate portion 81 abuts on the surface 35 of the back plate 31 by surface contact and covers the surface 35. The shim 71 is an integrally molded product formed by pressing from a single plate material. The shim 71 has a main plate portion 81 attached to the back plate 31 with grease or the like, and is attached to the back plate 31 integrally. The shim 71 may be provided with an engaging claw that engages with the back plate 31, and the shim 71 may be elastically attached to the back plate 31.

  As shown in FIG. 6, the shim 71 has a plurality of locking claws 91 cut and raised from the main plate portion 81. The locking claw 91 includes an extension part 92 extending perpendicularly from the main plate part 81 and a claw part protruding so as to be parallel to the main plate part 81 from the end of the extension part 92 opposite to the main plate part 81. 93. As shown in FIG. 4, these locking claws 91 are curved such that each extending portion 92 forms a part of the same cylinder, and as a result, the radius of the curve is the same and the center of the curve is Match. Each of the claw portions 93 of the locking claw 91 protrudes in a direction opposite to the center of curvature of the extension portion 92 with respect to the extension portion 92 at the base end of the protrusion. As shown in FIG. 5, the claw portions 93 of the locking claws 91 are arranged on the same plane parallel to the main plate portion 81.

  As shown in FIG. 1, the diameter of the circumscribed circle of the claw portions 93 of the plurality of locking claws 91 is larger than the inner diameter of the inner flange portion 63 of the piston 41 and slightly smaller than the inner diameter of the piston barrel portion 62. The diameter of the circumscribed circle of the plurality of extending portions 92 is slightly smaller than the inner diameter of the inner flange portion 63 of the piston 41. The length of the portion between the main plate portion 81 and the claw portion 93 of the extending portion 92 of the plurality of locking claws 91 is longer than the axial length of the inner flange portion 63 of the piston 41 by a predetermined value.

  In the shim 71, a plurality of locking claws 91 are engaged with the inner flange portion 63 of the piston 41. In other words, the extending portions 92 of the plurality of locking claws 91 are elastically deformed so that the diameter of the circumscribed circle of the plurality of claw portions 93 is smaller than the inner diameter of the inner flange portion 63. Are inserted into the inner flange portion 63 of the piston 41, and the extending portions 92 of the plurality of locking claws 91 are in a state where the claw portions 93 of the plurality of locking claws 91 are positioned closer to the piston bottom 61 than the inner flange portion 63. Release the elastic deformation. Then, the diameter of the circumscribed circle of the plurality of claw portions 93 becomes larger than the inner diameter of the inner flange portion 63. As a result, the disengagement between the shim 71 and the piston 41 is controlled by the plurality of claw portions 93 coming into contact with the inner flange portion 63.

  In the axial direction of the piston 41, the shim 71 can separate the main plate portion 81 from the piston 41 to a position where the plurality of claw portions 93 abut against the inner flange portion 63, and the piston 41 of the main plate portion 81 beyond that. Separation from is regulated. Further, in the axial direction of the piston 41, the shim 71 can approach the piston 41 until the main plate portion 81 abuts the piston 41. In addition, the plurality of claw portions 93 and the piston 41 can slide relative to each other in the axial direction of the piston 41.

  Therefore, the plurality of locking claws 91 of the shim 71 and the inner flange portion 63 of the piston 41 are provided on the friction pad 13 and the piston 41 to allow the friction pad 13 and the piston 41 to be separated within a predetermined distance, A regulating unit 101 that regulates the separation exceeding the predetermined distance is configured. The restricting portion 101 can hold the friction pad 13 and the piston 41 in a separated state within a range within the predetermined distance. In other words, the restricting portion 101 does not generate a force in a direction in which the friction pad 13 and the piston 41 are separated from each other within the predetermined distance. In other words, the restricting portion 101 connects the friction pad 13 and the piston 41 so as to be freely movable in the axial direction of the piston 41 within a range within the predetermined distance. The restriction portion 101 is provided on the shim 71 and the piston 41 of the friction pad 13.

  In the first embodiment, when the brake fluid pressure in the fluid pressure chamber 65 of the caliper 15 rises and this brake fluid pressure acts on the piston 41, the piston 41 moves forward toward the disk 11 with respect to the cylinder 46. 7, the main plate 81 of the shim 71 of the inner friction pad 13 disposed between the piston 41 and the disk 11 is abutted to press the friction pad 13 toward the disk 11. As a result, the inner friction pad 13 moves and contacts the disk 11. At this time, in the shim 71 of the friction pad 13, the claw portions 93 of the plurality of locking claws 91 are separated from the inner flange portion 63 of the piston 41 by a predetermined distance δ.

  Further, the caliper body 40 slides with respect to the mounting member (not shown) by the reaction force of the pressing and moves in the disk axial direction, and the claw portion 48 shown in FIG. 1 is disposed between the claw portion 48 and the disk 11. The outer friction pad 14 is pressed toward the disk 11. As a result, the outer friction pad 14 contacts the disk 11. In this way, the caliper 15 presses the disc 11 with both sides of the pair of friction pads 13 and 14 by the piston 41 and the claw portion 48 by the operation of the piston 41. As a result, the pair of friction pads 13 and 14 imparts friction resistance to the disk 11 to generate a braking force. The caliper 15 is a fist type caliper.

  Here, as described above, when the piston 41 moves forward toward the disk 11 with respect to the cylinder 46, the seal member 42 provided in the cylinder 46 has a portion on the inner peripheral side in contact with the piston 41 together with the piston 41. It is elastically deformed in the seal groove 55 so as to move to the disk 11 side. At this time, as shown in FIG. 2, since the tapered surface 58 is formed on the cylinder opening 50 side (left side in FIG. 2) on the radially inner side of the seal groove 55, the seal member 42 can be more elastically deformed. It is possible.

  When the hydraulic pressure of the brake fluid introduced into the hydraulic pressure chamber 65 of the caliper 15 decreases from the state of braking shown in FIG. 7, the piston 41 has a restoring force of elastic deformation of the seal member 42, so-called rollback, As shown in FIG. 8, the cylinder 46 is retracted to the side opposite to the disk 11.

  At this time, the frictional force of the friction pad 13 against the mounting member (not shown) is set to be sufficiently larger than the rollback force of the sealing member 42. Therefore, the friction pad 13 is prevented from moving by a frictional force with respect to a mounting member (not shown), and the plurality of claw portions 93 of the shim 71 are connected to the inner flange portion 63 of the piston 41 as shown in FIG. The piston 41 comes into contact and is caught, and the piston 41 is prevented from further retracting. That is, the restricting portion 101 including the plurality of locking claws 91 of the friction pad 13 and the inner flange portion 63 of the piston 41 restricts the separation between the friction pad 13 and the piston 41 exceeding a predetermined distance δ. As a result, the movement of the piston 41 in the direction opposite to the disk 11 with respect to the cylinder 46 is restricted within the range of the predetermined distance δ.

  Then, the seal member 42 returns to the state before elastic deformation in a state where the movement of the piston 41 is regulated by the friction pad 13 in this way. Thereafter, as shown in FIG. 9, the friction pad 13 moves in a direction away from the disk 11 with respect to the piston 41 and the cylinder 46 within a predetermined distance δ due to the vibration of the disk 11.

  The restriction portion 101 includes an extension portion 92 in which a part of the shim 71 along the back plate 31 extends in the piston axial direction, and a claw portion 93 (locking) in which an end portion of the extension portion 92 is bent in the piston radial direction. Part). In the restricting portion 101, when the piston 41 moves relative to the shim 71, the claw portion 93 is locked to the inner peripheral portion of the piston 41.

  The disc brake described in Patent Document 1 is provided with a groove in the opening end of a piston, and a shim provided with a locking claw that is elastically engaged with the groove. In such a configuration, the friction pad basically moves integrally with the piston. Therefore, after braking, if the rollback amount by the piston seal member is small and the piston cannot be retracted sufficiently, the friction pad and the disc There is a possibility that the gap becomes narrow, and the friction pad is dragged by the swing of the disk. For example, if the seal member is worn out due to aging or wear of the friction pad, the piston cannot be sufficiently retracted. In order to suppress dragging of the friction pad, the rollback amount by the piston seal member may be increased so that the piston can be returned even if the restoring force of the seal member is reduced. However, if it does in this way, in the state where the restoring force of the sealing member is not lowered, the rollback amount becomes too large. Then, the retraction amount of the piston becomes large, the invalid stroke increases, and the responsiveness at the next braking is affected.

  On the other hand, the disc brake 10 of the first embodiment allows the friction pad 13 and the piston 41 to be separated within the predetermined distance δ of the friction pad 13 and the piston 41 and restricts the separation exceeding the predetermined distance δ. 101 is provided. For this reason, even if the rollback amount by the seal member 42 of the piston 41 is increased so as to suppress dragging, the piston 41 can be prevented from moving backward beyond the predetermined distance δ after braking. Therefore, it is possible to prevent the return amount from becoming excessive while ensuring the return of the piston 41 after braking. Therefore, the response at the time of the next braking is improved while suppressing the drag of the friction pad 13. In addition, since abnormal wear of the friction pad 13 can be suppressed, the effect of extending the life of the friction pad 13 and reducing brake squeal is obtained.

  Further, in the disc brake 10 of the first embodiment, since the restricting portion 101 is provided on the shim 71 and the piston 41, an increase in cost for providing the restricting portion 101 can be suppressed.

  A plurality of locking claws 91 may be provided on the back plate 31 instead of the shim 71. For example, a plurality of locking claws 91 that are separate from the back plate 31 can be fixed to the back plate 31 by welding or caulking. In that case, it arrange | positions so that the shim 71 and piston 41 may not contact | abut to a welding part or a caulking part. Of course, it is easier to manufacture by forming the plurality of locking claws 91 by cutting and raising the shim 71 made of a single plate as in the first embodiment, and the cost can be greatly reduced.

[Second Embodiment]
Next, the second embodiment will be described mainly based on FIGS. 10 to 15 with a focus on differences from the first embodiment. In addition, about the site | part which is common in 1st Embodiment, it represents with the same name and the same code | symbol.

  The second embodiment includes a piston 41A that is partially different from the piston 41 of the first embodiment. As shown in FIG. 10, the piston 41 </ b> A has a small-diameter portion 111 whose outer diameter is smaller than the other portion on the opposite side of the piston bottom portion 61 of the piston body portion 62, and the piston bottom portion of the small-diameter portion 111. An outer flange portion 63 </ b> A that protrudes radially outward from the small diameter portion 111 is formed at the end opposite to the piston 61 and opposite to the piston bottom 61 of the piston body portion 62. The small-diameter portion 111 and the outer flange portion 63A are continuous over the entire circumference in the circumferential direction of the piston 41A, and form an annular shape.

  The second embodiment has an inner friction pad 13A that is partially different from the inner friction pad 13 of the first embodiment. As shown in FIGS. 11 and 12, the friction pad 13 </ b> A includes a pad main body 34 similar to that of the first embodiment and a shim 71 </ b> A that is partially different from the shim 71 of the first embodiment.

  The shim 71A is also an integrally molded product formed by pressing from a single plate material, and a plurality of locking claws partially different from the first embodiment cut and raised from the main plate portion 81 similar to the first embodiment. 91A. The locking claw 91 </ b> A extends from the main plate part 81 in the same manner as in the first embodiment, and extends parallel to the main plate part 81 from the opposite side of the main plate part 81 of the extension part 92. It has the nail | claw part 93A different from 1st Embodiment which protrudes. Each of the claw portions 93A of the locking claw 91A protrudes in the direction of the center of curvature of the extension portion 92 with respect to the extension portion 92 at the base end of the protrusion. The claw portions 93A of the locking claws 91A are arranged on the same plane parallel to the main plate portion 81.

  The diameter of the inscribed circle of the claw portions 93A of the plurality of locking claws 91A is smaller than the outer diameter of the outer flange portion 63A of the piston 41A shown in FIG. 10 and slightly larger than the outer diameter of the small diameter portion 111. The diameter of the inscribed circle of the plurality of extending portions 92 is slightly larger than the outer diameter of the outer flange portion 63A of the piston 41. The length of the portion between the main plate portion 81 and the claw portion 93A of the extending portion 92 of the plurality of locking claws 91A is longer than the axial length of the outer flange portion 63A of the piston 41 by a predetermined value.

  In the shim 71A, the plurality of locking claws 91A are engaged with the outer flange portion 63A of the piston 41A. In other words, by elastically deforming the extending portions 92 of the plurality of locking claws 91A, the diameters of the inscribed circles of the plurality of claw portions 93A are made larger than the outer diameter of the outer flange portion 63A. The outer flange portion 63A of the piston 41A is inserted inside the claw 91A, and the claw portions 93A of the plurality of locking claws 91A are positioned closer to the piston bottom 61 than the outer flange portion 63A. The elastic deformation of the extending part 92 is released. Then, the diameter of the inscribed circle of the plurality of claw portions 93A becomes smaller than the outer diameter of the outer flange portion 63A, thereby causing the shim 71A and the piston 41A to be disengaged, and the plurality of claw portions 93A are connected to the outer flange portion 63A. It will be in the state controlled by contacting.

  In the axial direction of the piston 41A, the shim 71A can separate the main plate portion 81 from the piston 41A to a position where the plurality of claw portions 93A abut against the outer flange portion 63A, and the piston 41A of the main plate portion 81 beyond that. Separation from is regulated. Further, in the axial direction of the piston 41A, the shim 71A can approach the piston 41A until the main plate portion 81 comes into contact with the piston 41A. The plurality of claw portions 93A and the piston 41A are slidable relative to each other in the axial direction of the piston 41A.

  Therefore, the plurality of locking claws 91A of the shim 71A and the outer flange portion 63A of the piston 41A are provided on the friction pad 13A and the piston 41A to allow the friction pad 13A and the piston 41A to be separated within a predetermined distance, A restricting portion 101A that restricts the separation exceeding the predetermined distance is configured. The restricting portion 101A can hold the friction pad 13A and the piston 41A in a separated state within the predetermined distance. In other words, the restricting portion 101A does not generate a force in a direction in which the friction pad 13A and the piston 41A are separated from each other within the predetermined distance. In other words, the restricting portion 101A connects the friction pad 13A and the piston 41A so as to be freely movable in the axial direction of the piston 41A within a range within the predetermined distance. The restricting portion 101A is provided on the shim 71A and the piston 41A of the friction pad 13A.

  Also in the second embodiment, when the brake fluid pressure in the fluid pressure chamber 65 of the caliper 15 rises and this brake fluid pressure acts on the piston 41A, the piston 41A moves forward toward the disk 11 with respect to the cylinder 46. As shown in FIG. 13, the friction plate 13 </ b> A is pressed against the disk 11 by abutting against the main plate portion 81 of the shim 71 </ b> A of the inner friction pad 13 </ b> A disposed between the piston 41 </ b> A and the disk 11. As a result, the inner friction pad 13 </ b> A moves and contacts the disk 11. At this time, in the shim 71A of the friction pad 13A, the claw portions 93A of the plurality of locking claws 91A are separated from the outer flange portion 63A of the piston 41A by a predetermined distance δ.

  When the hydraulic pressure of the brake fluid introduced into the hydraulic pressure chamber 65 of the caliper 15 decreases after braking, the piston 41A causes the elastic deformation of the seal member 42, that is, a so-called rollback, so that the disk 11 and Is retracted to the other side. At this time, the movement of the friction pad 13A is suppressed by a frictional force with respect to the mounting member (not shown), and as shown in FIG. 14, the plurality of claw portions 93A of the friction pad 13A abut against the outer flange portion 63A of the piston 41A. The piston 41 </ b> A is prevented from further retreating. That is, the restricting portion 101A composed of the plurality of locking claws 91A and the outer flange portion 63A restricts the separation between the friction pad 13A and the piston 41A exceeding a predetermined distance δ. As a result, the movement of the piston 41A in the direction opposite to the disk 11 with respect to the cylinder 46 is restricted within a predetermined distance δ. Thus, the seal member 42 returns to the state before elastic deformation in a state where the movement of the piston 41A is restricted. Thereafter, as shown in FIG. 15, the friction pad 13 </ b> A moves in a direction away from the disk 11 with respect to the piston 41 </ b> A and the cylinder 46 within a predetermined distance δ due to the vibration of the disk 11.

  The restriction portion 101A includes an extension portion 92 in which a part of the shim 71A along the back plate 31 extends in the piston axial direction, and a claw portion 93A (locking portion) in which an end portion of the extension portion 92 is bent in the piston radial direction. Part). In the restricting portion 101A, when the piston 41A moves relative to the shim 71A, the claw portion 93A engages with the outer peripheral portion of the piston 41A.

  In the second embodiment, the friction pad 13A and the piston 41A are provided with a restricting portion 101A that allows the friction pad 13A and the piston 41A to be separated within a predetermined distance δ and restricts the separation exceeding the predetermined distance δ. For this reason, similarly to the first embodiment, it is possible to suppress the return amount of the piston 41A after braking from being excessive while suppressing the drag of the friction pad 13A.

  The first aspect of the embodiment described above includes a friction pad that faces a disk, a piston that presses the friction pad against the disk, a cylinder that has a bore portion that movably accommodates the piston, and the bore A disc brake provided with a seal member disposed in a seal groove of a portion and contacting the piston, wherein the friction pad and the piston are allowed to be separated within a predetermined distance of the friction pad and the piston. However, a restricting portion for restricting the separation exceeding a predetermined distance is provided. Thereby, it is possible to suppress an excessive return amount of the piston after braking while suppressing dragging of the friction pad.

  According to a second aspect, in the first aspect, the friction pad includes a lining that contacts the disk, a back plate provided on a surface of the lining opposite to the disk, and the lining of the back plate. A shim covering the opposite surface, and the restricting portion is provided on the shim and the piston.

  According to a third aspect, in the second aspect, the restriction portion includes an extension portion in which a part of the shim along the back plate extends in the piston axis direction, and an end portion of the extension portion A locking portion bent in a piston radial direction, and when the piston moves relative to the shim, the locking portion locks to an inner peripheral portion or an outer peripheral portion of the piston. .

DESCRIPTION OF SYMBOLS 10 Disc brake 11 Disc 13, 13A Friction pad 31 Back plate 33 Lining 36 Surface 41, 41A Piston 42 Seal member 46 Cylinder 51 Bore part 55 Seal groove 71, 71A Shim 101, 101A Control part

Claims (3)

A friction pad facing the disc;
A piston that presses the friction pad against the disk;
A cylinder having a bore for movably accommodating the piston;
A disc brake comprising: a seal member disposed in a seal groove of the bore portion and contacting the piston;
The disc brake according to claim 1, wherein the friction pad and the piston are provided with a restricting portion that allows the friction pad and the piston to be separated within a predetermined distance and restricts the separation beyond the predetermined distance. The friction pad is
A lining in contact with the disc;
A back plate provided on the surface of the lining opposite to the disk;
A shim that covers the surface of the back plate opposite to the lining;
The disc brake according to claim 1, wherein the restricting portion is provided on the shim and the piston. The restricting portion includes an extending portion in which a part of the shim along the back plate extends in the piston axial direction, and an engaging portion in which an end portion of the extending portion is bent in the piston radial direction. Have
3. The disc brake according to claim 2, wherein when the piston moves relative to the shim, the engaging portion is engaged with an inner peripheral portion or an outer peripheral portion of the piston.

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